The purpose of this study is to examine the feasibility to deliver PBI before the lumpectomy is performed. By administering the PBI before the lumpectomy, a smaller volume of breast tissue may be exposed to radiation. The PBI method used in this study is 3D (three dimensional) conformal external beam irradiation. 3D-conformal external beam irradiation uses an x-ray beam to deliver the radiation dose. Approximately 3 weeks after completion of the PBI, the cancer will be surgically removed.